2011MNRAS.413L..11L

Using a simple accelerating model and an assumption that γ-rays originate from p-p collisions for a π⁰ model, we investigate γ-ray sources like V407 Cygni in symbiotic stars. The upper limit of their occurrence rate in the Galaxy is between 0.5 and 5/yr, indicating that they may be important sources of high-energy γ-rays. The maximum energies of the accelerated protons mainly distribute around 10¹¹ eV, and barely reach 10¹⁵ eV. The novae occurring in D-type SSs with ONe white dwarfs and long orbital periods are good candidates for γ-ray sources. Due to a short orbital period which results in a short acceleration duration, the nova occurring in symbiotic star RS Oph cannot produce γ-ray emission like that in V407 Cygni.